Chemistry of 6H-pyrido[4,3-b]carbazoles. Part 12. Synthesis of potential bisintercalating drugs bearing two ellipticine units

Abstract

A number of bisellipticines have been synthesized in an attempt to increase the potency of the parent tetracycles as anti-cancer drugs through bis-intercalation into the same strand of DNA. The compounds described are structures in which two pyrido[4,3-b]carbazole units are joined at C-5 by an alkyl chain and two amide functions. The preparation of a number of new ellipticine ‘monomers’ is reported, as well as a synthesis of the alkaloid 5-formyl-11-methyl-6H-pyrido[4,3-b]carbazole. A novel oxidative coupling reaction of ellipticines has also been discovered.